Analyst Upgrades

• Akamai (AKAM) to overweight from neutral at Piper Jaffray.
• Las Vegas Sands (LVS) to buy from neutral at UBS.
• Aetna (AET) to Outperform from market perform at Leerink.
• Hot Topic (HOTT) to buy from neutral at Janney Capital.
• Colonial Properties (CLP) upgraded to Outperform from market perform at FBR Capital and to buy from hold at Citigroup.
• Altera (ALTR) to buy from hold at Citigroup.
• American Reprographics (ARC), CarMax (KMX) and American Campus (ACC) to outperform from neutral at RW Baird.
• Zebra Tech (ZBRA) to neutral from underweight at JPMorgan.
• IMAX (IMAX) to buy from hold at Canaccord.
• Basic Energy (BAS) to neutral from sell at Goldman.
• Mednax (MD) to buy from neutral at BofA/Merrill.
• UTi Worldwide (UTIW) to buy from hold at Stifel Nicolaus.

Analyst Upgrades

• Molycorp (MCP) to overweight from neutral at JPMorgan.
• Humana (HUM), HealthSpring (HS) and UnitedHealth (UNH) to buy from neutral at UBS.
• Williams Cos. (WMB) to conviction buy from neutral and UBS (UBS) to buy from neutral at Goldman.
• China Kanghui (KH) to overweight from neutral at Piper Jaffray.
• Arthur J. Gallagher (AJG) to buy from hold at Citigroup.
• Armstrong World (AWI) to buy from hold at BB&T.
• Time Warner (TWX) to buy from hold at Benchmark Co.
• Calpine (CPN) to overweight from equal weight at Barclays.
• 3M Company (MMM) to neutral from underperform and Kirby (KEX) to buy from underperform at BofA/Merrill.

Analyst Upgrades

• Aetna (AET) to buy from neutral at Goldman.
• Kellogg (K) to buy from neutral at UBS.
• PetSmart (PETM) to outperform from market perform at JMP Securities.
• NetApp (NTAP) and Scripps Networks (SNI) to buy from hold at Wunderlich.
• Thoratec (THOR) to buy from hold at Auriga.
• ArcelorMittal (MT) to overweight from neutral at HSBC.
• Bristol-Myers (BMY) to outperform from neutral at Cowen.
• Eaton Vance (EV) to neutral from sell at Ticonderoga.
• Adtran (ADTN) to buy from underperform at BofA/Merrill.

UnitedHealth Group's (UNH) stock is a little sick today. The shares are exchanging hands at a quote of $40.07 as of this writing, a price that represents a drop in value of 1.2%. Volume is active.

If you look at the latest earnings report, however, you can't help but shake your head in wonderment. The Associated Press says that adjusted Q4 net income of $1.05 per share beat the overall projection of 84 cents per share. Quite a difference. Furthermore, the company is sticking to its outlook for 2011.

Analyst Upgrades

• Exxon Mobil (XOM) and BB&T (BBT) to outperform from perform at Oppenheimer.
• D.R. Horton (DHI) upgraded to outperform from market perform at Wells Fargo.
• Meritage Homes (MTH), Old Dominion Freight (ODFL) and Heartland Payment (HPY) to outperform from market perform at Wells Fargo.
• Toll Brothers (TOL) to overweight from equal weight at Barclays.
• Hershey (HSY) to buy from neutral at Janney Capital.
• UnitedHealth (UNH), Cigna (CI) and Allscripts (MDRX) to buy from hold at Deutsche Bank.
• Nationwide Health (NHP) to outperform from market perform at JMP Securities.
• Reynolds American (RAI) to buy from neutral at UBS.
• Adtran (ADTN), PG&E (PCG) and Wisconsin Energy (WEC) to overweight from equal weight at Morgan Stanley.

Analyst Upgrades

• GC Financial upgraded Microsoft (MSFT) to buy from hold, citing expectations that the company will raise its quarterly dividend by 15%. The firm upped its target for shares to $30 from $29.
• JPMorgan upgraded Agrium (AGU) to overweight from neutral, citing valuation and strengthening agricultural fundamentals. The firm raised its target for shares to $75 from $70. Note JPMorgan downgraded Mosaic (MOS) this morning to neutral from overweight.
• Susquehanna upgraded Baker Hughes (BHI) to positive from neutral based on valuation. The firm has a $53 target on the stock.
• Target (TGT) was upgraded to buy from neutral at BofA/Merrill.
• CF Industries (CF) was upgraded to conviction buy from neutral at Goldman.
• Portugal Telecom (PT) was upgraded to buy from hold at Deutsche Bank.

Analyst Upgrades

• Deutsche Bank upgraded Illinois Tool Works (ITW) to buy from hold, citing valuation and the company's strong revenue performance. The firm has a $60 price target for shares.
• Goldman upgraded PPD Inc. (PPDI) to buy from hold and raised its price target to $31 from $28. The firm expects strong top line growth and bookings momentum for the upgrade.
• Stifel Nicolaus upgraded Insituform Technologies (INSU) to buy from hold based on higher estimates for sewer rehab and energy. The firm has a $31 target on the stock.
• Patterson-UTI Energy (PTEN) was upgraded to overweight from equal weight at Morgan Stanley.
• Wisconsin Energy (WEC) and Northeast Utilities (NU) were upgraded to buy from neutral at UBS.
• Rockwell Collins (COL) was upgraded to buy from neutral at BofA/Merrill.

Analyst Upgrades

• Oppenheimer upgraded ConocoPhillips (COP) to outperform from perform after the company sold its stake in Syncrude. The firm has a $70 price target for shares.
• Leerink upgraded UnitedHealth (UNH) to outperform from market perform. The firm sees upside to the company's 2010 guidance and finds shares attractively valued at currently levels.
• Citigroup upgraded both Mirant (MIR) and RRI Energy (RRI) to hold from sell after the two companies agreed to merge.
• Cooper Companies (COO) was upgraded to outperform from market perform at FBR Capital.
• Expedia (EXPE) was upgraded to conviction buy from neutral at Goldman.
• A123 Systems (AONE) was upgraded to buy from hold at Deutsche Bank.

Analyst Upgrades

• UBS upgraded Starbucks (SBUX) to buy from neutral, citing expectations for sales momentum. The firm raised its price target to $29 from $27.
• Piper Jaffray upgraded Sonic (SONC) two notches to overweight from underweight on expectations the company's sales and margin trends are set to improve. The firm raised its target price for shares to $12 from $8.
• BMO Capital upgraded Chicago Bridge & Iron (CBI) to outperform from market perform, citing its outlook for earnings growth. The firm has a $30 target on the stock.
• Clorox (CLX) was upgraded to overweight from equal weight at Barclays.
• Alexion Pharma (ALXN) was upgraded to conviction buy from buy at Goldman.
• Compellent (CML) was upgraded to buy from hold at ThinkEquity.

As always, there is a volume of speculation after the much anticipated release of the quarterly changes in holdings report from Berkshire Hathaway (BRK.A). While leaving all the deep analytical number crunching for greater minds than my own, I'd like to take a look at what Warren Buffett could be telling us through his company's latest form 13F.

Why has Warren Buffett swallowed Burlington Northern Santa Fe (BNI) while letting go of Norfolk Southern (NSC) and Union Pacific (UNP)? Being the master of due diligence, Mr. Buffett has most likely determined that BNI is the most attractive of the three. The future of rail transport is all but guaranteed to shine, and I believe that Mr. Buffett has exited the other two rail companies simply to avoid conflict of interest issues.